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We have read with great interest the letter by Li et al. [1]. We fully agree that individualized adjustment of physical exercise programs in older adults is essential, considering specific characteristics such as biological sex and frailty or pre-frailty status. These factors significantly influence physiological, functional, and clinical responses to exercise and therefore must be carefully considered. In addition, other factors, such as cognitive and affective status, sarcopenia, bone health, body composition, fall risk, specific diseases such as cancer or diabetes, individual preferences, care setting (hospital, nursing home, community), polypharmacy, nutritional status, genetic aspects, social support, and safety considerations should also be considered when prescribing exercise in older adults. The benefits of physical exercise in older adults are now indisputable, and the remaining challenge is for health professionals to acknowledge that it is probably unethical not to prescribe exercise in this population when frailty is present [2]. It is unquestionable that primary health care should be the first level of care for this population; therefore, the FRAILMERIT project aimed to analyze whether an intervention designed within this setting was feasible and effective to reach the largest possible population. Primary care is often constrained by patient overload, and highly complex interventions or those requiring demanding assessments may compromise the implementation of such programs. Spanish primary care currently lacks a broadly implemented, structured exercise-prescription program for frail and pre-frail older adults, which constrains the feasibility of delivering highly individualized, protocolized multicomponent exercise in everyday practice. Consequently, it seemed necessary to begin by implementing initial, pragmatically designed exercise programs, even if they did not incorporate fine-grained tailoring or distinct intervention pathways for each frailty phenotype, with the aim of escalating toward more individualized approaches, aligned with the precision and person-centred medicine. For these reasons, and following the rationale of FRAILMERIT, the priority at this stage was to develop and test a viable, scalable, and extensive intervention in its reach for frailty management in primary care, to ensure real-world applicability and sustainability [3]. From a sex-based perspective, older men and women exhibit relevant differences in body composition, muscle mass and strength, bone mineral density, cardiovascular function, and hormonal regulation. These differences influence adaptations to strength, endurance, and balance training. For example, older women, particularly after menopause, show a higher prevalence of sarcopenia and osteoporosis, requiring careful prescription of strength and progressively loaded mechanical exercises, with a strong emphasis on safety and injury prevention. In contrast, older men may experience greater absolute gains in strength but also bear a higher burden of cardiovascular comorbidity, necessitating tight evaluation and monitoring of aerobic exercise. However, differential exercise prescriptions between men and women are not yet clearly established. While some studies have reported greater functional improvements in women than in men following exercise programs during hospitalization [4], others have found similar responses to resistance training in both sexes [5], or no differences in exercise-induced endothelial sensitivity between healthy postmenopausal women and age-matched men [6]. Frailty and pre-frailty, on the other hand, represent a dynamic continuum of physiological vulnerability that critically modulates exercise indications, tolerance, and benefits. Initial exercise prescription should focus on improving strength, followed by balance training, and finally endurance training to enable walking or performing daily activities. In addition, starting with low-intensity exercises, duration, frequency, and intensity is recommended, followed by a progressive increase. In FRAILMERIT, exercises were adapted according to baseline SPPB scores, using elastic bands of varying resistance tailored to participants' characteristics, with gradual intensity progression, in reduced groups and under expert supervision [3]. This approach allows older adults to adapt to new physical demands and reduces the risk of injury or excessive fatigue. Despite the need for adaptations, clinical studies have shown that older adults with advanced frailty and multiple comorbidities, although they may struggle with vigorous or high-intensity aerobic exercise, are highly capable of performing high-intensity resistance training even at very advanced ages, including nonagenarians and centenarians [7-9]. Ignoring sex and frailty status among other factors in exercise prescription may lead to suboptimal interventions, lower adherence, reduced effectiveness, and even an increased risk of adverse events in older adults. Conversely, stratifying exercise programs according to these variables maximizes functional and clinical benefits, in line with the principles of person-centered geriatric medicine. For all these reasons, we agree with Li that it is essential to personalize, adjust, and manage exercise prescription in older adults as rigorously as any other medical treatments [10]. Pedro Abizanda, Adriana Abizanda Saro, Rubén Alcantud Córcoles, Rafael García Molina: Design of the work, drafting of the work, final approval of the version to be published, agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All authors had a role in writing the final manuscript and approved the final version. This work was supported by the “Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación y Unión Europea—Fondo Europeo de Desarrollo Regional, Health Research Projects call 2019 of the Health Strategic Action 2017-2020: PI19/00962,” and by “Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, España. Ayuda cofinanciada por el Fondo Europeo de Desarrollo Regional FEDER Una Manera de hacer Europa (Grant number CB16/10/00408).” There is no role of the Sponsor. The authors declare no conflicts of interest. This publication is linked to a related Letter to the Editor by Li and Wang. To view this article, visit https://doi.org/10.1111/jgs.70411.